The separation of cells from their extracellular matrix (ECM) is commonly achieved through centrifugation. Typically, the cells are pelleted and the extracellular supernatant is aspirated following the centrifuging step.
There is an increasing interest in microsampling, i.e. sample volumes of the order of 1.0 to 100 μL. By way of example, it is straightforward to extract a small volume of human whole blood into a capillary device such as a pipette tip following a finger prick with a sterile blood lancet. Typically 50 to 80 μL in volume is collected. In the context of bioparticles in general or cells in particular, such small volumes are not easy to centrifuge and so the traditional methods of sample preparation using centrifugation become problematical. Moreover, there is an interest in microsampling strategies where the sample can be processed using automated pipetting platforms such as the Tecan Genesis 200 or strategies remote from an actual laboratory environment, where centrifuges may not be readily available. A simple example of such a context is the analysis of blood samples collected by skin pricking, e.g. from a finger, in humans. Thus, sample collection and preparation can often be a bottleneck in the process of developing a robust and reliable point-of-care device from microsampling and testing.
It is an object of the present invention to at least in part address the limitations of sample preparation techniques based on centrifugation, and to thereby provide improvements suitable for use in microsampling techniques.